Return-path: Received: from nick.hrz.tu-chemnitz.de ([134.109.228.11]:58650 "EHLO nick.hrz.tu-chemnitz.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751910Ab3GHO4S (ORCPT ); Mon, 8 Jul 2013 10:56:18 -0400 From: Simon Wunderlich To: Johannes Berg Cc: linux-wireless@vger.kernel.org, Mathias Kretschmer , Simon Wunderlich Subject: [PATCHv6 03/18] mac80211: fix timing for 5 MHz and 10 MHz channels Date: Mon, 8 Jul 2013 16:55:51 +0200 Message-Id: <1373295366-12823-4-git-send-email-siwu@hrz.tu-chemnitz.de> (sfid-20130708_172039_754095_C0694710) In-Reply-To: <1373295366-12823-1-git-send-email-siwu@hrz.tu-chemnitz.de> References: <1373295366-12823-1-git-send-email-siwu@hrz.tu-chemnitz.de> Sender: linux-wireless-owner@vger.kernel.org List-ID: according to IEEE 802.11-2012 section 18, various timings change when using 5 MHz and 10 MHz. Reflect this by using a "shift" when calculating durations. Signed-off-by: Simon Wunderlich Signed-off-by: Mathias Kretschmer --- Changes to PATCHv5: * fix minor error which was accidently fixed in the following patch of this series Changes to PATCHv4: * remove obsolete ieee80211_local_get_divisor() * change divisor to shift to avoid unnecesary integer divisions Changes to PATCHv3: * don't use hw.conf * remove net/mac80211/rc80211_minstrel_ht.c modifications --- net/mac80211/ieee80211_i.h | 31 +++++++++++++++++++++++++++- net/mac80211/rc80211_minstrel.c | 30 +++++++++++++++++++++------ net/mac80211/rc80211_minstrel_ht.c | 5 +++-- net/mac80211/tx.c | 10 ++++++--- net/mac80211/util.c | 39 ++++++++++++++++++++++++------------ 5 files changed, 90 insertions(+), 25 deletions(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 8412a30..d0bd15d 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -809,6 +809,34 @@ ieee80211_get_sdata_band(struct ieee80211_sub_if_data *sdata) return band; } +static inline int +ieee80211_chandef_get_shift(struct cfg80211_chan_def *chandef) +{ + switch (chandef->width) { + case NL80211_CHAN_WIDTH_5: + return 2; + case NL80211_CHAN_WIDTH_10: + return 1; + default: + return 0; + } +} + +static inline int +ieee80211_vif_get_shift(struct ieee80211_vif *vif) +{ + struct ieee80211_chanctx_conf *chanctx_conf; + int shift = 0; + + rcu_read_lock(); + chanctx_conf = rcu_dereference(vif->chanctx_conf); + if (chanctx_conf) + shift = ieee80211_chandef_get_shift(&chanctx_conf->def); + rcu_read_unlock(); + + return shift; +} + enum sdata_queue_type { IEEE80211_SDATA_QUEUE_TYPE_FRAME = 0, IEEE80211_SDATA_QUEUE_AGG_START = 1, @@ -1465,7 +1493,8 @@ extern void *mac80211_wiphy_privid; /* for wiphy privid */ u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len, enum nl80211_iftype type); int ieee80211_frame_duration(enum ieee80211_band band, size_t len, - int rate, int erp, int short_preamble); + int rate, int erp, int short_preamble, + int shift); void mac80211_ev_michael_mic_failure(struct ieee80211_sub_if_data *sdata, int keyidx, struct ieee80211_hdr *hdr, const u8 *tsc, gfp_t gfp); diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c index 5b25966..a507376 100644 --- a/net/mac80211/rc80211_minstrel.c +++ b/net/mac80211/rc80211_minstrel.c @@ -382,14 +382,18 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta, static void calc_rate_durations(enum ieee80211_band band, struct minstrel_rate *d, - struct ieee80211_rate *rate) + struct ieee80211_rate *rate, + struct cfg80211_chan_def *chandef) { int erp = !!(rate->flags & IEEE80211_RATE_ERP_G); + int shift = ieee80211_chandef_get_shift(chandef); d->perfect_tx_time = ieee80211_frame_duration(band, 1200, - rate->bitrate, erp, 1); + DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1, + shift); d->ack_time = ieee80211_frame_duration(band, 10, - rate->bitrate, erp, 1); + DIV_ROUND_UP(rate->bitrate, 1 << shift), erp, 1, + shift); } static void @@ -425,14 +429,17 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband, struct ieee80211_rate *ctl_rate; unsigned int i, n = 0; unsigned int t_slot = 9; /* FIXME: get real slot time */ + u32 rate_flags; mi->sta = sta; mi->lowest_rix = rate_lowest_index(sband, sta); ctl_rate = &sband->bitrates[mi->lowest_rix]; mi->sp_ack_dur = ieee80211_frame_duration(sband->band, 10, ctl_rate->bitrate, - !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1); + !!(ctl_rate->flags & IEEE80211_RATE_ERP_G), 1, + ieee80211_chandef_get_shift(chandef)); + rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef); memset(mi->max_tp_rate, 0, sizeof(mi->max_tp_rate)); mi->max_prob_rate = 0; @@ -441,15 +448,22 @@ minstrel_rate_init(void *priv, struct ieee80211_supported_band *sband, unsigned int tx_time = 0, tx_time_cts = 0, tx_time_rtscts = 0; unsigned int tx_time_single; unsigned int cw = mp->cw_min; + int shift; if (!rate_supported(sta, sband->band, i)) continue; + if ((rate_flags & sband->bitrates[i].flags) != rate_flags) + continue; + n++; memset(mr, 0, sizeof(*mr)); mr->rix = i; - mr->bitrate = sband->bitrates[i].bitrate / 5; - calc_rate_durations(sband->band, mr, &sband->bitrates[i]); + shift = ieee80211_chandef_get_shift(chandef); + mr->bitrate = DIV_ROUND_UP(sband->bitrates[i].bitrate, + (1 << shift) * 5); + calc_rate_durations(sband->band, mr, &sband->bitrates[i], + chandef); /* calculate maximum number of retransmissions before * fallback (based on maximum segment size) */ @@ -547,6 +561,7 @@ minstrel_init_cck_rates(struct minstrel_priv *mp) { static const int bitrates[4] = { 10, 20, 55, 110 }; struct ieee80211_supported_band *sband; + u32 rate_flags = ieee80211_chandef_rate_flags(&mp->hw->conf.chandef); int i, j; sband = mp->hw->wiphy->bands[IEEE80211_BAND_2GHZ]; @@ -559,6 +574,9 @@ minstrel_init_cck_rates(struct minstrel_priv *mp) if (rate->flags & IEEE80211_RATE_ERP_G) continue; + if ((rate_flags & sband->bitrates[i].flags) != rate_flags) + continue; + for (j = 0; j < ARRAY_SIZE(bitrates); j++) { if (rate->bitrate != bitrates[j]) continue; diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c index 5256297..7475a7a 100644 --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -862,8 +862,9 @@ minstrel_ht_update_caps(void *priv, struct ieee80211_supported_band *sband, mi->sta = sta; mi->stats_update = jiffies; - ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1); - mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1) + ack_dur; + ack_dur = ieee80211_frame_duration(sband->band, 10, 60, 1, 1, 0); + mi->overhead = ieee80211_frame_duration(sband->band, 0, 60, 1, 1, 0); + mi->overhead += ack_dur; mi->overhead_rtscts = mi->overhead + 2 * ack_dur; mi->avg_ampdu_len = MINSTREL_FRAC(1, 1); diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 4105d0c..3523daa 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -40,7 +40,7 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, struct sk_buff *skb, int group_addr, int next_frag_len) { - int rate, mrate, erp, dur, i; + int rate, mrate, erp, dur, i, shift; struct ieee80211_rate *txrate; struct ieee80211_local *local = tx->local; struct ieee80211_supported_band *sband; @@ -153,6 +153,8 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, rate = mrate; } + shift = ieee80211_vif_get_shift(&tx->sdata->vif); + /* Don't calculate ACKs for QoS Frames with NoAck Policy set */ if (ieee80211_is_data_qos(hdr->frame_control) && *(ieee80211_get_qos_ctl(hdr)) & IEEE80211_QOS_CTL_ACK_POLICY_NOACK) @@ -162,7 +164,8 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, * (10 bytes + 4-byte FCS = 112 bits) plus SIFS; rounded up * to closest integer */ dur = ieee80211_frame_duration(sband->band, 10, rate, erp, - tx->sdata->vif.bss_conf.use_short_preamble); + tx->sdata->vif.bss_conf.use_short_preamble, + shift); if (next_frag_len) { /* Frame is fragmented: duration increases with time needed to @@ -171,7 +174,8 @@ static __le16 ieee80211_duration(struct ieee80211_tx_data *tx, /* next fragment */ dur += ieee80211_frame_duration(sband->band, next_frag_len, txrate->bitrate, erp, - tx->sdata->vif.bss_conf.use_short_preamble); + tx->sdata->vif.bss_conf.use_short_preamble, + shift); } return cpu_to_le16(dur); diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 2265445..61856e1 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -107,7 +107,8 @@ void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx) } int ieee80211_frame_duration(enum ieee80211_band band, size_t len, - int rate, int erp, int short_preamble) + int rate, int erp, int short_preamble, + int shift) { int dur; @@ -118,6 +119,9 @@ int ieee80211_frame_duration(enum ieee80211_band band, size_t len, * * rate is in 100 kbps, so divident is multiplied by 10 in the * DIV_ROUND_UP() operations. + * + * shift may be 2 for 5 MHz channels or 1 for 10 MHz channels, and + * is assumed to be 0 otherwise. */ if (band == IEEE80211_BAND_5GHZ || erp) { @@ -130,15 +134,21 @@ int ieee80211_frame_duration(enum ieee80211_band band, size_t len, * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext * * T_SYM = 4 usec - * 802.11a - 17.5.2: aSIFSTime = 16 usec + * 802.11a - 18.5.2: aSIFSTime = 16 usec * 802.11g - 19.8.4: aSIFSTime = 10 usec + * signal ext = 6 usec */ dur = 16; /* SIFS + signal ext */ - dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */ - dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */ + dur += 16; /* IEEE 802.11-2012 18.3.2.4: T_PREAMBLE = 16 usec */ + dur += 4; /* IEEE 802.11-2012 18.3.2.4: T_SIGNAL = 4 usec */ dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10, 4 * rate); /* T_SYM x N_SYM */ + + /* IEEE 802.11-2012 18.3.2.4: all values above are: + * * times 4 for 5 MHz + * * times 2 for 10 MHz + */ + dur *= 1 << shift; } else { /* * 802.11b or 802.11g with 802.11b compatibility: @@ -168,7 +178,7 @@ __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, { struct ieee80211_sub_if_data *sdata; u16 dur; - int erp; + int erp, shift = 0; bool short_preamble = false; erp = 0; @@ -177,10 +187,11 @@ __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, short_preamble = sdata->vif.bss_conf.use_short_preamble; if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE) erp = rate->flags & IEEE80211_RATE_ERP_G; + shift = ieee80211_vif_get_shift(vif); } dur = ieee80211_frame_duration(band, frame_len, rate->bitrate, erp, - short_preamble); + short_preamble, shift); return cpu_to_le16(dur); } @@ -194,7 +205,7 @@ __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, struct ieee80211_rate *rate; struct ieee80211_sub_if_data *sdata; bool short_preamble; - int erp; + int erp, shift = 0; u16 dur; struct ieee80211_supported_band *sband; @@ -210,17 +221,18 @@ __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, short_preamble = sdata->vif.bss_conf.use_short_preamble; if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE) erp = rate->flags & IEEE80211_RATE_ERP_G; + shift = ieee80211_vif_get_shift(vif); } /* CTS duration */ dur = ieee80211_frame_duration(sband->band, 10, rate->bitrate, - erp, short_preamble); + erp, short_preamble, shift); /* Data frame duration */ dur += ieee80211_frame_duration(sband->band, frame_len, rate->bitrate, - erp, short_preamble); + erp, short_preamble, shift); /* ACK duration */ dur += ieee80211_frame_duration(sband->band, 10, rate->bitrate, - erp, short_preamble); + erp, short_preamble, shift); return cpu_to_le16(dur); } @@ -235,7 +247,7 @@ __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, struct ieee80211_rate *rate; struct ieee80211_sub_if_data *sdata; bool short_preamble; - int erp; + int erp, shift = 0; u16 dur; struct ieee80211_supported_band *sband; @@ -250,15 +262,16 @@ __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, short_preamble = sdata->vif.bss_conf.use_short_preamble; if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE) erp = rate->flags & IEEE80211_RATE_ERP_G; + shift = ieee80211_vif_get_shift(vif); } /* Data frame duration */ dur = ieee80211_frame_duration(sband->band, frame_len, rate->bitrate, - erp, short_preamble); + erp, short_preamble, shift); if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) { /* ACK duration */ dur += ieee80211_frame_duration(sband->band, 10, rate->bitrate, - erp, short_preamble); + erp, short_preamble, shift); } return cpu_to_le16(dur); -- 1.7.10.4